To latescan

ABSTRACT

A JOB IS CREATED AND A JOB CONTROL UNIT RECORDS THE AMOUNT OF MAIN STORAGE REQUIRED AS WELL AS THE HANDICAP PLUS BIAS WHICH WILL DETERMINE HOW FAST THE JOB WILL BE PROMOTED TO THE MULTIPROGRAMMING SET OF JOBS CURRENTLY BEING PERFORMED BY THE SYSTEM. WAITING JOBS ARE ASSIGNED DIFFERENT HANDICAPS BASED UPON THEIR EXTERNAL PRIORITIES. JOBS ADDED LATER HAVE HIGHER HANDICAPS BY THE AMOUNT OF A BIAS INCREMENTED UPON EACH PROMOTION UNTIL IT IS SO LARGE THAT ALL HANDICAPS MUST BE DECREMENTED BY THE AMOUNT OF THE BIAS. IN THIS WAY EARLIER JOBS HAVE LOWER HANDICAPS WITH TIME AND EVENTUALLY EVEN JOBS WITH HIGH INITIAL HANDICAPS RECEIVE SERVICE AT THE RATE INTENDED WITH RESPECT TO JOBS WITH LOWER HANDICAPS. JOBS WHICH ARE INTERACTIVE AND LATE ARE PLACED IN A LATE QUENCE FOR FASTER SERVICE, TO ASSURE INTERACTIVE USERS FASTER SERVICE. ON DEMOTION A JOB RECEIVES A FEEDBACK ADJUSTMENT OF ITS HANDICAP BY MEANS OF A K FACTOR ADJUSTMENT. JOBS ARE SCHEDULED TO PROVIDE ADEQUATE RESPONSE TIME AND EQUITABLE ALLOCATION OF SYSTEM RESOURCES.

EFENSEVE ULKQATIUN UNITED STATES PATENT AND TRADEMARK OFFICE Published at the request of the applicant or owner in accordance with the Notice of Dec. 16,1969, 869 O.G. 687. The abstracts of Defensive Publication applications are identified by distinctly numbered series and are arranged chronologically. The heading of each abstract indicates the number of pages of specification, including claims and sheets of drawings contained in the application as originally filed. The files of these applications are available to the public for inspection and reproduction may be purchased for 30 cents a sheet.

Defensive Publication applications have not been examined as to the merits of alleged invention. The Patent and Trademark Oflice makes no assertion as to the novelty of the disclosed subject matter.

PUBLISHED OCTOBER 7, 1975 T93Ji09 SCHEDULING MECHANESM FOR INTERACTHVE SYSTEMS WITH VIRTUAL MEMORY Donald Dean Chamherlin, San Jose, Calif., assignoi' to International Business Machines Corporation, Armonlr,

Filed Mar. 13, 1974, Ser. No. 450,621 Int. Cl. G06f 9/12 US. Cl. 444-1 5 Sheets Drawing. 7 Pages Specification so 1061's comm muss sun a; some an H RCESLEXEC oximr mo SIZ[S,SUNOFU1ERRALPRIORIIIES n IIHESIAMP REilllMLRARDlCAPlEVEllNI 6 AND RUHBER or JOBS RRENT MNDI BIAS uonxmcso sumss) AVE nuns FozHYiRS m JOB is minor BLOCK FROM ALL OUEUiS msnu we mm NGRHALRUEUE n WW5 PRIOR! 35 BURKE!" RAHDICAP 30 uvom rue-mu in ms J'S EORTRDL BLOCK; moms" PRIWIH mm ion All has or SYSTEM s1 mmnruci mm" m rs u zg mn our PRIOR 195 J [NBS BY INHRACTIDH RiSU J08 1'5 RICBRDS FOR RESOURCE AND EXECUHRR HNE USH'I 1015M; SIT

YIMESTAKF Al REALTINES AND RESOURCES USED VALUE UPDAIE lAliSCAN SCAN All JOBS 0R NORIAL 0 [0R MR JOB! ON RORKALG If JUB I IS INTERRCYIVY MD LHL SHORT IN DURATION H1AND DE LAYED NDRI UIRH HIKE 2, [MN

RKNUVE Hi0! NGRNAL OUEUE AND PLACE Ill ITS CURREC! ORDKR Bl HHESTANP PUT J08 IN RBRHAL DIJEUE BY CURRENT HANDICAP A job is created and a job control unit records the amount of main storage required as well as the handicap plus bias which will determine how fast the job will be promoted to the multiprogramming set of jobs currently being performed by the system. Waiting jobs are assigned diiferent handicaps based upon their external priorities. Jobs added later have higher handicaps by the amount of a bias incremented upon each promotion until it is so large that all handicaps must be decremented by the amount of the bias. In this Way earlier jobs have lower handicaps with time and eventually even jobs with high initial handicaps receive service at the rate intended with respect to jobs with lower handicaps. Jobs which are interactive and late are placed in a late queue for faster service, to assure interactive users faster service. On demotion a job receives a feedback adjustment of its handicap by means of a K factor adjustment. Jobs are scheduled to provide adequate response time and equitable allocation of system resources.

Original Filed Mar. 13, 1974 JOBJ CREATED SET JOB JS CONTROL BLOCK RESOURCES & EXECUTION TIME USED=O TIMESTAMP=REALTIME,HANDICAP LEVELIHI=AVG CHANGE SYSTEM OTYS NJOBS,SUM EXTERNAL Sheet 1 of 5 JOB J IS DESTROYED CHANGE SUM OF WORKING SET SIZES, SUM OF EXTERNAL PRIORITIES AND NUMBER OF JOBS PRIORITIES,SUM WSS I 15\ INSERT JOB INTO NORMALOUEUE BY JOB CHANGES PRIORITY CURRENT HANDICAP so UPDATE PRIORITY IN JOB JS CONTROL BLOCK; INCREMENT PRIORITY TOTAL JOB PROMOTED FOR ALL JOBS IN SYSTEM BY DIFFERENCE I5\ I. I BETWEEN JOB JS NEW AND OLD DELETE JOB POINTER FROM LATE PRIORITIES OUEUE 0R NORMAL OUEUE I JOBIJ ENDS BY I INCREASE BIAS BYI I INTERACTION 31 32 I I? RESET JOB JS RECORDS FOR RESOURCES 7L LARGEST REPRESIP? AND EXECUTION TIME USED TO ZERO; SET

I NO I TIMESTAMP AT REAL TIMES AND RESOURCES IRE ELIMINATE BIAS FROM HANDICAP USED VALUE UPDATE.

SET BIAS TOZERO -I JOB DEMOTED R I LATESCAN COMPUTE NEW HANDICAP SCAN ALL JOBS 0N NORMAL 0 FOR EACH JOBI 0N NORMAL Q 22 v COMPUTE NEW TIME SLICE IF JOB I IS INTERACTIVE AND LATE,

LENGTH OFJOBS SHORT IN DURATION TOAND DE- 25 H IS JOB INTERACTIVE AND LATE BY TIMESTAMP PUT JOB IN NORMAL OUEUE BY CURRENT HANDICAP LAYED MORE THAN TIME T2, THEN REMOVE FROM NORMAL OUEUE AND PLACE IN ITS CORRECT ORDER BY TIMESTAMP Oct. 7, 1975 DD. CHAMBERLIN T939,009

SCHEDULING MECHANISM FOR INTERACTIVE SYSTEMS WITH VIRTUAL Original Filed Mar. 13, 1974 FIG .2 JOB I IS PROMOTED Sheet 2 of 5 FIND THE POINTER TO JOB J'S CONTROL 1 BLOCK ON NORMAL O OR LATE O AND DELETE IT FROM THE OUEUE.

INCREASE BIAS BY 1. /I6

IS BIAS= THE LARGEST H REPRESENTABLE NUMBER? I NO YES

SCAN ALL JOBS ON NORMAL O. FOR EACH JOB I, DECREASE HANDICAP HANDICAP (I) HANDICAP (II- BIAS RESET BIAS T0 ZERO.

L T0 LATESCAN 1a FIG.3

LATESCAN SCAN ALL JOBS ON NORMAL .0.

FOR EACH JOBI ON NORMALO I8 EXIT Oct. 7, 1975 Original Filed Mar. 13, 1974 D.D. CHAMBERLIN SCHEDULING MECHANISM FOR JOB J IS DEMOTED M 20 Fl G 4 OOMPUTE THE NEW HANDICAP OF JOB J ACCORDING TO THE FOLLOWING STEPS AGGUM PAGE SEG(J) AGGUM PAGE SEG(JI+WSS(J)*AGTIVEJIME(J); SYS PAGE SEO=SYS PAGE SEO+WSS(J)*AGTIVE TIME(J);

(NOTE IF THE ABOVE ADDITION MAKES SYS PAGE SEO LARGER THAN THE LARGEST REPRESENTABLE NUMBER, SUBTRAGT THE LARGEST REPRESENTABLE NUMBER FROM IT AND STORE THE RESULT.)

AOGUM EXEG(J)=ACGUM EXEG (J)+ SLIGE LENGTH(J)SLIOE REMAINING (JI) K=AGGUM PAGE SEG(J)*SUM PRIORITIES/(NJOBS PRIORITY(J)*(SYS PAGE SEG'SYSTEM (NOTE IN THE ABOVE, IF SYS-PAGE SEG-SYSTEM STAMP(J)IS NEGATIVE, INCREASE IT -STAMPIJIII;

BY THE LARGEST REPRESENTABLE NUMBER AND USE THE RESULT IN THE COMPUTATION.)

IF K I+THRESHOLD THEN H LEVEL(J)=H LEVEL(J)+DELTA; IF K I-THRESHOLD THEN II LEvEIIJ)=H HANDICAP (J)=H LEVEL(J)+BIAS;

COMPUTE THE NEW TIME SLICE LENGTH OF JOB J ACCORDING TO THE FOLLOWING STEPS 7 suII wss SUM WSS+WSS(J)-OLD WSS (J) /22 OLD- WSS (J)= WSS(J), SLIGE-LENGTH (J) =AVERAGE SLICE *WSSU) NJOBS/SUM WSS-,

SLIOE REMAINING(J)=SLIGE LENGTH(J);

IS JOB J INTERACTIVE AND LATE 23 ACCUM EXEC(J) T1 & REAL TIME-TIME STAMP(J T2 YES N0 INSERT JOBJ INTO NORMAL Q IN ITS GORREGT ORDER BY HANDICAP (J) INSERT JOB J ONTO LATE Q IN ITS GORREGT ORDER BY TIMESTAMP (J) TO LATESOAN 18 Oct. 7, 1975 DD. CHAMBERLIN T939,009

SCHEDULING MECHANISM FOR INTERACTIVE SYSTEMS WITH VIRTUAL Original Filed Mar. 13, 1974 Sheet 4 of 5 Fl G. 5

/1o JOB J IS CREATED INITIALIZE JOB J'S CONTROL BLOCK:

ACCUM PAGE SEC (J) =0; AOCUM EXEC (J) =0;

TIMESTAMP (J)= REALJIME; SYSTEM STAMP (J SYS PAGE SEC;

H LEVEL(J)=AVERAGE 0F HELEVEL S OF ALL KNOWN JOBS. HANDICAP(J)=H LEVEL(J)+BIAS;

WSS (J),0LD WSS(J)= SUM WSS/NJOBS; SL|CE LENGTH (J) SLICLREMAINING (J)=AVERAGE SL|CE-,

CHANGE RELEVANT SYSTEM 0UANT|T|ES= 12 NJOBS NJOBS +1",

SUM PRIORITIES= SUM PRIORITIES+ PRIORITYU), SUM WSS=SUM WSS+WSS (J);

INSERT JOB J mm NORMAL Q IN ITS CORRECT ORDER /15 BY HANDICAPU).

T0 LATESCA N 18 Oct. 7, 1975 DD. CHAMBERLIN T939,009

SCHEDULING MECHANISM FOR INTERACTIVE SYSTEMS WITH VIRTUAL Original Filed Mar. 13, 1974 Sheet 5 of 5 F I G 6 JOB J IS DESTROYED 26 CHANGE RELEVANT SYSTEM OUANTITIES= SUM WSS=SUM WSS-WSS(J); SUM PRIORITIES= SUMJRIORITIES-PRIORITY(J);

NJOBs NJOBS-I;

DELETE ALL POINTERS TO JOB J'S CONTROL /28 BLOCK FROM ALL OUEUES.

TO LATESCAN 18 F I G 7 JOB J CHANGES PRIORITY UPDATE PRIORITY (J) IN JOB J'S CONTROL BLOCK. JOB J COMPLETES AN INTERACTION INCREMENT SUM PRIORITIES BY THE DIFF- ERENCE BETWEEN JOB J'S NEW AND OLD PRIORITIES RESET JOB J'S CONTROL BLOCIO- /52 ACCUM PAGE SEC(J)= O; ACCUM EXEOIJI=O',

TIMESTAMPIJ) REAL TIME; SYSTEM STAMP(J)=SYS PAGE SEC;

T0 LATESOAN I8 

